Follow rest for lathes



April 1951 E. N. LICHTENBERG 2,547,529

- FOLLOW REST FOR LATHES Filed April 14, 1949 2 Sheets-Sheet 1 If EDWARD NLIEI-ITENBERB Gttornegs April 3, 1951 E. N. LICHTENBERG 2,547,529

FOLLOW REST FOR LATHES Filed April 14, 1949 2 Sheets-Sheet 2 Zmnentor EDWARD N. LIEHTENEIER'E Cittornegs Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE FOLLOW BEST FOR LATHES Edward N. Lichtenberg, Claymont Heights, Del., assignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application April 14, 1949, Serial No. 87,404

F 6 Claims. v l

The present invention relate to an improved follow rest for machines for turning, grinding, or the like, and more particularly such machines used in the manufacture of gun and rifle barrels and similar work having a relatively long thin shaft of circular cross section. An object of the invention is to provide a follow rest adapted for mounting directly upon the carriage of the machine, and including means arranged to bear on the turned portion of the barrel or other work in proximity to the cutting, grinding or similar tool to provide evenly distributed support for the work, to the end that the tendency of the tool to throw the work off center is resisted and the concentricity of the work is maintained. It is par- 3 ticularly proposed, in the illustrated exemplary embodiment of the invention, to provide three rolls mounted on bell crank and equally spaced around the periphery of the work a short distance behind the tool, these rolls being constrained to move in substantially radial arcs in exactly equal amounts, so that when the center of the three rolls is on the spindle center line of the machine the concentricity of the turned portion of the work is maintained, the resultant pressure of the rolls on the work counter-balancing the tool pressure. :It is further proposed to provide fluid pressure means, as for instance an air cylinder, for providing the pressure for maintaining the rolls in engagement with the work,- and whereby the 1 rolls are automatically maintained in engagement with the work under controlled pressures as the rolls move radially to accommodate the changing diameter of the work as the turning, grinding .or similar operation progresses.

.A further object is to provide a follow rest having self-aligning rolls having a relatively large area of contact with the work and adapted to align themselveswith the changing contour of the work throughout its length, to the end that a substantial total pressure may be applied to the rolls without excessive unit pressures, such as may-be encountered when there is a small area or point contact of the rolls with the work. With the relatively high roll pressures that are necessary to support the barrel or other work against the tool pressure, this small area or point contact .may result in unit pressures in excess of the elastic limit of the barrel steel with consequent =objectionable reaction upon the barrel structure.

With the above and other objects in view, an embodiment of the invention is shown in the accompanying drawings, and this embodiment will be hereinafter more fully described with reference thereto, and the invention will be finally pointed outin theclaims.

In the drawings-- Fig. '1 .is a .front elevation of the ifollow .rest,

according to the illustrated exemplary embodiment of the inventionjthe amebeing shown par- Lil 2 tially in vertical section, and the dot-and-dash lines indicating a lathe carriage to which the follow rest is attached.

Fig. 2 is a top plan view.

Fig. 3 is a vertical sectional view, taken along the staggered line 3-3 of Fig. 1.

Fig. 4 is a side elevation, as seen from the left in Fig. 1..

Fig. '5 is a fragmentary sectional View, on an enlarged scale, showing one of the pressure rolls and certain associated parts.

Similar reference characters indicate corresponding parts throughout the several figures of the drawings.

Referring to the drawings, the follow rest, according to the illustrated exemplary embodiment of the invention, comprises, a body member, indie cated generally as 10, having a generally circular upper portion l-i upon which the pressure rolls are mounted, as will presently more fully appear, and provided with a central opening l2 for passage of the barrel being turned, and having .a generally rectangular lower portion 13 provided with screw holes 14 for securing the body memher by :means of screws it to the side of the lathe carriage 18- toward the tail stock ll. The rearward side of the body member is provided with a peripheral reinforcing flange l8 and radially arranged reinforcing webs l 9.

Upon the outer side of the body member there is provided a pedestal bracket 26 having a recess 26 in its upper face in which is secured .a double-acting ai-r cylinder 22 provided witha pis-v ton :23wextending downwardly from the cylinder F into a cylindrical opening 2 in the bracket. A

vertically reciprocating rod 25 is connected at its upper end to the lowerend-of the piston by a coupling 26 and is guided at its lower end by a cylindrical plunger extension 2i engaged in the vere tical passage 23 of a bearing portion 29 proi/iided upon the outer side of the body member in verti- .cal line with the air cylinder. An adjustable screw plug 30 having a central air hole Lil is provided in the lower end of the passage .23 to limit the downward movement .of the rod he rod .25 is provided with a vertical slot 32 havinga cross pin 3-3 extending acros it, this pin being pivotally mounted in the rod and having opposed flats B l-34 engaged by the slotted end '35 of the operating arm 36 .of the pressure roll operating camplate or spider 31. V

The cam plate '31 is rotatably mounted upon the forward face of the .body member, being provided with .a cylindrical bearing opening .38 en- .gaged by .a hearing bushing '39, secured in the opening 12 .of the 'body member by a clamping .nut '48, screwed upon "its rearward threaded end portion 41 within an annular recess '42 surroundring the opening "1'2. The bushing project forwardly from the body member, being provided with an annular shoulder 43 engaging the face of the body member and with a flange 44 engaging the face of the cam plate, the distance between the bushing 43 and the flange 44 being slightly greater than the thickness of the cam plate 37, so that the cam plate can rotate freely on the bush.- mg.

The cam plate 31 is provided with three side edges defined by the three sides of an equilateral triangle, the operating arm 36 projecting from one corner and having its slotted end 35 in radial line with the turning axis of the plate.

Outwardly of the three sides of the cam plate there are pivotally mounted upon the face of the body member i three bell crank rocker arms 35 equally spaced from each other and from the turning axis of the lathe, each having a hub portion 46 rotatably engaged upon a collared stud 41 having its shank secured in a hole 48 of the body member by a nut 49, the hub being rotatably retained upon the stud by a bearing washer E! and a retaining screw 5!. Upon the outer end of each rocker arm there is provided a collared stud 52 having its shank secured in a hole 53 in the rocker arm by a clamping washer 54 and screw 55. A cam roller 56 is rotatably mounted on the stud 52 of each rocker arm and is engaged in a cam slot 51 provided along the adiacent side of the cam plate. This cam slot is defined at its inner side by the flat surface of the side of the cam plate and at its outer side and ends by a yoke member 58 secured upon the side of the cam plate by screws 5959, the angle of the cam slot being such that as the cam plate is rotated in counter-clockwise direction from the position as shown in Fig. l the cam roller is moved outwardly and the inner end of the rocker arm is moved inwardly. As may be noted in the preceding paragraph and from an inspection of Fig. 1 of the drawing, one edge of each cam slot is defined by one of the side edges of the cam plate, those side edges each being one side of an equilateral triangle. A slot so formed engages the corresponding roller 56 at a relatively sharp angle and a substantial component of any radially inward force applied to the roller 56 will tend to produce a rotation of the cam plate in the clockwise direction. Upon the inner end of each rocker arm there is provided a collared stud 60 having its shank secured in a hole 61' in the rocker arm by a clamping screw 52. A pressure roll 53 is rotatably mounted upon the stud 66 by means of an interposed ball bearing unit consisting of a row of balls 65, an inner race 55 secured upon the stud by a clamping screw 35, an

outer race 6i secured within the pressure roll against an internal shoulder 58 by means of a retaining ring 69, and sealing rings lfi-l0 arranged between the inner and outer races at each side of the calls. The ball unit is of a self-aligning type wherein sufiicient clearance is provided to enable the outer ball race to have limited tilting movement with respect to the inner ball race, the maximum tilt being of the order of about 5. This permits the pressure roll to have a relatively large area of surface contact with the barrel being turned, while at the same time allowing the pressure roll to follow the taper of the barrel as the turning progresses, and as indicated by the dot-and-dash lines in Fig. 5. The periphery of the pressure roll is of cylindrical form, which is permitted by virtue of the self-aligning bearing.

The pressure rolls and their associated parts are enclosed in a guard H secured to the forward face of the body member by screws 12 engaged through blocks 13 welded or otherwise suitably secured to the inner side of the peripheral wall of the guard. The peripheral Wall of the guard is provided at its outer side with a slot opening 14 through which the operating arm 36 of the cam plate 31 extends, and the front wall is provided with a circular opening concentric to the turning center of the lathe, a circular insert plate 16 having a central circular opening 11 being secured therein by screws 18 engaged in inwardly projecting lugs F9 secured to the guard. The lower side of the guard is open to allow coolant fluid and chips that may enter it to flow therefrom. At its lower inwardly disposed corner there is provided a clearance recess 80, in which the cross feed 8| carrying the cutting tool 82 engages in the forwardly disposed position of the tool, as shown in Figs. 1 and 2, the cross feed being mounted in the usual manner upon dovetail guideways 83 provided upon the longitudinally mov able carriage IE.

A suitable coolant fluid, as for instance a mixture of soluble oil and water, is directed to the tool by a tube 84 mounted upon a fixture 85 secured by a screw 86 upon the upper side of the body member it, this fixture having a suitable passag therethrough in communication with the supply line 87 for the coolant. The outlet end of the tube 84 is so disposed that chips and shav-- ings are effectually removed from the work as they are produced by the tool, so that the barrel will be free of chips and other foreign matter at its area adjacent the tool which is engaged by the pressure rolls. The sealed bearings of the pressure rolls are such that they are effectually protected against the entrance of the coolant fluid, chips, and other foreign matter.

The operation is as follows: The gun or rifie barrel 88 to be turned is mounted between the head stock spindle 89 and the tail stock spindle 98 carried by the tail stock H, as shown in Fig. 3, the carriage i6 and the follow rest mounted thereon being in the starting position clear of the gun barrel, with the tail stock spindle 90 projected through the opening 77 of the guard and its mounting chuck disposed within the bushing 38. In this position the pressure rolls are in outwardly moved position, the piston 23 being raised as shown in Fig. 1. Air pressure is ad mitted to the cylinder 22 to force the piston 23 downwardly causing the cam plate 21 to be r0- tated in counter-clockwise direction and the pressure rolls to be swung inwardly into contact with the tail stock spindle 90 at three equally spaced points around its periphery, the diameter of the spindle being the same as the turned barrel diameter. As the carriage moves axially along the barrel, the rolls leave the tail stock spindle and bear on the turned portion of the barrel following the contour thereof as shown in the dot-dash lines in Fig. 3. Although it is obvious that such an arrangement will readily follow over a section of decreasing diameter, it may not have been made clear that the preferred and most accurate operation results from using the follow rest as shown in the drawing by moving it in the direction of increasing diameter. The wedging action of a section of increasing diameter will exert a powerful force, which, as a result of the relatively sharp angle of the cams, may overcome the force of the air piston 23 and reverse the rotation of the cam plate. In this way, backlash or play in the sys tem is completely eliminated. The cam plate imparts exactly the same motion to each of the pressure rolls, and consequently if thev rolls are lined up so that their inscribed circle is in line with the lathe spindle and tail stock, this alignment is maintained regardless of the diameter of the inscribed circle. With no tool pressure tending to throw the barrel off center, it is evident that the pressure of the rolls on the barrel is equal for all three rolls. The action of the cutting tool on the barrel as it is turned normally tends to throw the barrel off center. As this occurs, however, the roll pressures redistribute themselves, exerting a resultant pressure on the barrel which counter-balances the tool pressure and thus maintains the concentricity of the turned portion of the barrel.

The form of the invention illustrated in the drawings and described herein is typical and illustrative only, and it is evident that the invention is capable of embodiments in other forms, all falling within the scope of the appended claims, which are to be broadly construed.

What is claimed is:

1. In a follow rest for machines for turning, grinding, or the like, a body member adapted for attachment to the tool-carrying carriage of the machine having an opening arranged for passage of the work, a plurality of equally spaced circumferentially arranged work engaging pressure rolls movably mounted on said body member having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, a self-aligning bearing supporting each of said rolls for limited tilting movement, roll actuating means for simultaneously and equally imparting work engaging or disengaging movement to said rolls, and pressure means for urging said roll actuating means in Work engaging direction.

2. In a follow rest for machines for turning, grinding, or the like, a body member adapted for attachment to the tool-carrying carriage of the machine having an opening arranged for passage of the work, a plurality of equally spaced circumferentially arranged work engaging pressure rolls movably mounted on said body member having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, a self-aligning bearing supporting each of said rolls for limited tilting movement, each of said rolls having a substantially cylindrical peripheral surface, roll actuating means for simultaneously and equally imparting work engaging or disengaging movement to said rolls, and pressure means for urging said roll actuating means in work engaging direction.

3. In a follow rest for machines for turning, grinding, or the like, a body member adapted for attachment to the tool-carrying carriage of the machine having an opening arranged for passage of the work, a plurality of equally spaced circumferentially arranged Work engaging pressure rolls movably mounted on said body member having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, a cam member mounted on said body member for rotary movement about the turning center of the lathe for simultaneously and equally imparting work engaging or disengaging movement to said rolls, the engagement of said cam member with said rolls being such as to cause reverse movement of said cam by pressure exerted on said rolls, and yieldable pressure means for urging said cam member in work engaging direction.

4. In a follow rest for machines for turning,

grinding, or the like, a body member adapted for attachment to the tool-carrying carriage of the machine having an opening arranged for passage of the Work, a plurality of equally spaced circumferentially arranged roll-supporting bellcrank levers pivotally mounted on said body member and having inner and outer ends, work engaging pressure rolls respectively carried upon the inner ends of said levers having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, cam-engaging means respectively carried upon the outer ends of said levers, cam means engaged with said cam-engaging means for simultaneously and equally imparting work engaging or disengaging movement to said levers, and pressure means for urging said cam means in work engaging direction.

5. In a follow rest for machines for turning, grinding, or the like, a body member adapted for attachment to the tool-carrying carriage of the machine having an opening arranged for passage of the Work, a plurality of equally spaced circumferentially arranged roll-supportin bellcrank levers pivotally mounted on said body member and having inner and outer ends, workengaging pressure rolls respectively carried upon the inner ends of said levers having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, cam rollers respectively carried upon the outer ends of said levers, cam means having a plurality of cam slots respectively engaged by said cam rollers for simultaneously and equally imparting work-engaging or disengaging movement to said levers, and pressure means for urging said cam means in work engaging direction.

6. In a follow rest for machines for turning,

grinding, or'the like, a body member adapted for attachmentto the tool-carrying carriage of the machine having an opening arranged for passage of the Work, a plurality of equally spaced circumferentially arranged roll-supporting bellcrank levers pivotally mounted on said body member and having inner and outer ends, work engaging pressure rolls respectively carried upon the inner ends of said levers having their turning centers coincident to an inscribed circle concentric to the turning center of the machine, cam-engaging means respectively carried upon the outer ends of said levers, cammeans mounted on said body member for rotary movement about the turning center of the machine for simultaneously and equally imparting work engaging or disengaging movement to said levers, a radially extending arm carried by said cam means, and fluid pressure means including a piston operatively connected to said arm for urging said cam means in work engaging or disengaging direction.

EDWARD N. LICHTENBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

